Cylinder locks



1964 R. H. BALESTRINI 3,

CYLINDER LOCKS Filed June 19, 1961 III] 01A II lVI/AIII] I'll/l IIM BY Q JLJ.

United States Patent 3,151,477 CYLINDER LOCKS Roberto Horacio Balestrini, 243 Ombu St., Martinez, Buenos Aires, Argentina Filed June 19, 1961, Ser. No. 136,118 2 Claims. Cl. 7t3421) The object of the present invention isan improved cylinder lock of practical inviolability, in view of the fact that its particular characteristics provide a superior degree of safety to that of similar locks known at present.

More concretely expressed, the novelty of the present invention consists in a cylinder lock, the access whereto by the key is displaced in respect to the plane of action of same and is obstructed by elements provided specially to this end.

All cylinder locks can be picked by means of a process of probing, a matter well known to professional picklocks, said process being performed by introducing a thin strip of metal into the key-hole and then giving a gentle rotary movement to the cylinder, while testing the locking plungers in turn along the spring line of the cylinder, unlocking same, one by one, and maintaining them in unlocked position by taking advantage of the frictional resistance produced by the slight rotary movement of the cylinder.

The object of the instant invention arose out of the search for a way in which to prevent the use of this picklock method and this object consists of a novel structure which can be realized in a variety of special forms, as will be described hereinafter.

For the sake of clarity, only the improvements will be described in detail, whilst those parts that are known to those skilled in the art are referred to only in order to explain the working of the improved cylinder lock. It is to be understood, therefore, that in general the invention relates to cylinder locks of the type consisting of a housed cylinder fitting rotatably within a cylindrical cavity provided in a solid body having a series of radial, cylindrical borings of small diameter in a row along its spring line, facing another row of similar borings in said solid body, each opposing pair of borings housing an axially slidable plunger and the respective compression spring housed in the boring of the solid body. The sliding plungers are normally held in the rotatable cylinder in response to the action of the said springs, said plungers being of dilfering lengths. The rotary cylinder has a longitudinal internal opening, or key passage, extending along the row of the smaller borings in order to permit the entry of the stem of a key provided with indentations that coincide with and are capable of engaging the interior extremities of the said cylindrical plungers.

Briefly stated, the invention resides in that the cylinder lock includes an obstructing device against the introduction of a probe or any other lock-picking tool, said obstruction being avoidable only by the proper key for opening the lock.

The foregoing and other objects, advantages, and features of the invention, and the manner in which the same are accomplished will become more readily apparent upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings, which illustrate a preferred and exemplary embodiment of the invention and a possible, obvious modification of the same and wherein:

FIGURE 1 is a vertical section through a cylinder lock devised according to the present invention;

FIGURE 2 is a more schematic section of a modified cylinder lock, also provided with the improvements of the present invention;

FIGURE 3 is a side elevation view of a key made of 3,151,477 Patented Oct. 6, 1964 bent rod, suitable for use with a lock having a key passage of circular section; and

FIGURE 4 is a side elevation of a key made of a stamped sheet metal, suitable for use with a lock having a substantially flat key passage.

Referring to the drawing, the cylinder lock devised according to the present invention, consists of a rotary cylinder I able to turn within a solid body 2, having a series of radial, cylindrical borings of small diameter in a row along its spring line, facing another row of similar borings in the solid body, each opposing pair of borings housing an axially slidable plunger 3, whilst the corresponding compression spring is housed in the boring of the solid body 2. Furthermore, the cylinder 1 is provided with another boring near the entry of the lock facing a bother in the solid body 2, and these borings house respective axially slidable plungers 4, biased by a compression spring in the bore of the body. The slidable plunger or obstructing element 4 is also placed along the spring line of the rotary cylinder 1. The diameter of the plunger or obstructing element 4 is greater than the width of the longitudinal, internal passage or key-hole 5, formed in the cylinder 1. This passage 5 is adapted for the operation position of a key, but the entry to the said passage 5 is displaced in respect of the straight-line prolongation A-B of the straight edge of the key-stem 7, when in correct position to open the lock. When in said unlocking position, the obstructing element 4 extends past the said prolongation of the line A-B at its free end 8. The movement of said element 4, which is also a locking element by itself in the bore that houses it, is greater than the movements of the plunger 3 in the respective bores in which they are slidably housed.

The key 6 that corresponds to the improved lock has a stem the profile whereof shows three longitudinal angular portions, as will be seen, the inner and outer portions being parallel with each other, while the intermediate portion forms a bent connection between them, the angle of which varies at will.

The object of the present invention is attained by the manner in which this device acts and is described below:

As can be seen in FIGURE 1, in order to succeed in disengaging the plungers 3 to enable the cylinder 1 to rotate, the outer plunger 4, which obstructs and locks at the same time, must be moved into that position where its free end 8 rests at a point below the prolongation of the line A-B. It will be readily understood that this position is not obtainable by means of any kind of probe, as a portion of the plunger 4 must be pushed into its corresponding bore in the solid body 2, which Will prevent the effective action of any probe, since the greater movement of the plunger 4, than that of the plungers 3, does not allow a sufiicient angle of rotation of the cylinder 1 within the solid body 2 to give the frictional pressure that holds the plungers 3 displaced by the probe, that is necessary when violating the lock.

FIGURE 1 shows one of the embodiments that can be developed by following out the idea of the instant invention without crossing the boundary line of protection, but many different modifications can be introduced, such as, for instance, a variation in the number of locking plungers, a different number of obstructing elements and their position in relation to the former, changes in the shape of the key passage and that of the key, which, in its turn, can be made by casting, or by machining, changing the section of said key passage, which can be flat, cylindrical, oval, or curved and can have fluting and straight or curved longitudinal slots or be plain.

In the case of the embodiment with a flat, longitudinal key passage, this can be eifected by machining the whole length of the rotary cylinder, which can then be fitted with a separate body, as shown in FIGURE 2, where said separate body 9 is attached by means of studs 10.

The keys 6 are made according to the form and section of the key passage 5, and two possible forms and types are illustrated in FIGURES 3 and 4. The curvature of the intermediate portion of the key-stern is adjusted to the length of the obstructing element 4 and forms a further security means of the lock.

The foregoing embodiment and the possible modifications are to be considered illustrative, rather than restrictive of the invention, and all further modifications which come Within the meaning and range of equivalency of the claims are to be included therein.

What I claim is:

1. A cylindrical type lock comprising, a body member having a cylindrical opening therein, a cylinder member within said opening for rotation within said body member, said body member having a series of radially dis posed borings in substantially axial alignment, a spring pressed radially slidable plunger in each boring urged towards the periphery of said cylinder, said cylinder member having a series of radially disposed borings each adapted to register with a boring in said body member, a radially slidable plunger element in each boring in said cylinder member, said cylinder member having a keyway with a portal at an end of the cylinder member and in communication with the borings therein, said keyway having a straight surface confronting said plunger elements throughout the inner portion of the keyway, said cylinder member having a radial bore adjacent the portal of the keyway in axial alignment with the borings in the cylinder, said body member having a radially disposed bore in axial alignment with said borings in the body member accommodating a spring pressed slidable plunger, an obstructing plunger in said bore in the cylinder member, and said keyway diametrically opposite said obstructing plunger being otfset radially outwardly from said inner portion of the keyway to accommodate the free end of said obstructing plunger so that the free end thereof extends across a continuation of a line defining the straight surface of the keyway in the locked position of the plungers.

2. A cylindrical type lock as set forth in claim 1, wherein the obstructing plunger is of greater lateral cross section than the width of the keyway.

References Cited in the file of this patent UNITED STATES PATENTS 261,789 Thompson July 25, 1882 758,025 Taylor Apr. 19, 1904 1,484,757 Coney Feb. 26, 1924 1,906,701 Maxwell et al. May 2, 1933 2,149,733 Hagendorn et al Mar. 7, 1939 2,247,621 Speer July 1, 1941 

1. A CYLINDRICAL TYPE LOCK COMPRISING, A BODY MEMBER HAVING A CYLINDRICAL OPENING THEREIN, A CYLINDER MEMBER WITHIN SAID OPENING FOR ROTATION WITHIN SAID BODY MEMBER, SAID BODY MEMBER HAVING A SERIES OF RADIALLY DISPOSED BORINGS IN SUBSTANTIALLY AXIAL ALIGNMENT, A SPRING PRESSED RADIALLY SLIDABLE PLUNGER IN EACH BORING URGED TOWARDS THE PERIPHERY OF SAID CYLINDER, SAID CYLINDER MEMBER HAVING A SERIES OF RADIALLY DISPOSED BORINGS EACH ADAPTED TO REGISTER WITH A BORING IN SAID BODY MEMBER, A RADIALLY SLIDABLE PLUNGER ELEMENT IN EACH BORING IN SAID CYLINDER MEMBER, SAID CYLINDER MEMBER HAVING A KEYWAY WITH A PORTAL AT AN END OF THE CYLINDER MEMBER AND IN COMMUNICATION WITH THE BORINGS THEREIN, SAID KEYWAY HAVING A STRAIGHT SURFACE CONFRONTING SAID PLUNGER ELEMENTS THROUGHOUT THE INNER PORTION OF THE KEYWAY, SAID CYLINDER MEMBER HAVING A RADIAL BORE ADJACENT THE PORTAL OF THE KEYWAY IN AXIAL ALIGNMENT WITH THE BORINGS IN THE CYLINDER, SAID BODY MEMBER HAVING A RADIALLY DISPOSED BORE IN AXIAL ALIGNMENT WITH SAID BORINGS IN THE BODY MEMBER ACCOMMODATING A SPRING PRESSED SLIDABLE PLUNGER, AN OBSTRUCTING PLUNGER IN SAID BORE IN THE CYLINDER MEMBER, AND SAID KEYWAY DIAMETRICALLY OPPOSITE SAID OBSTRUCTING PLUNGER BEING OFFSET RADIALLY OUTWARDLY FROM SAID INNER PORTION OF THE KEYWAY TO ACCOMMODATE THE FREE END OF SAID OBSTRUCTING PLUNGER SO THAT THE FREE END THEREOF EXTENDS ACROSS A CONTINUATION OF A LINE DEFINING THE STRAIGHT SURFACE OF THE KEYWAY IN THE LOCKED POSITION OF THE PLUNGERS. 